Voltage detection control device and voltage detection control method

Abstract

The invention discloses a voltage detection control device and a voltage detection control method.The voltage detection control device is applied to a BUCK circuit, the BUCK circuit comprises a solar photovoltaic panel and electric equipment, a relay switch is arranged between the solar photovoltaic panel and the electric equipment, and the voltage detection control device comprises an operational amplifier, a voltage detection module and a control module, the positive input end is connected with the voltage output end of the solar photovoltaic panel, and the negative input end is connected with the voltage output end of the electric equipment; the positive input end of the comparator is connected with first reference voltage, and the reverse input end is connected with the output end of the operational amplifier; the control end of the switching tube is connected with the output end of the comparator, the first pole is connected with the control end of the relay switch, and the second pole is grounded; according to the invention, the operational amplifier can be utilized to amplify the voltage difference between the photovoltaic device and the electric device, and the comparator is combined to set the reference threshold value, so that the sensitivity and speed of voltage detection are improved, and the use safety of the photovoltaic device and the electric device in the BUCK circuit is further effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and particularly to a voltage detection and control device and a voltage detection and control method. Background Art

[0002] Traditional BUCK circuits have significant safety hazards in photovoltaic charging or step-down applications: when the step-down MOS transistor shorts due to a fault, the input voltage will directly reach the load or electrical equipment, causing equipment damage; in addition, when the photovoltaic voltage is lower than the voltage of electrical equipment such as a battery, current backflow may occur, resulting in damage to the solar panel.

[0003] Existing protection schemes mostly rely on fuses or simple voltage comparators. However, fuses have a slow response speed and cannot be reused, while ordinary voltage comparators lack a dynamic amplification function and are difficult to accurately detect small voltage differences, resulting in insensitive protection thresholds or frequent misoperations. Therefore, there is an urgent need for a BUCK circuit protection technology that can detect voltage differences in real time, quickly respond to abnormal states, and intelligently control on and off to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art. It can use an operational amplifier to amplify the voltage difference between the photovoltaic and electrical equipment, and combine a comparator to set a reference threshold, significantly improving the detection sensitivity and detection speed of small voltage changes, avoiding misjudgments caused by noise or threshold deviations in traditional schemes, and thus effectively protecting the safety of electrical equipment and photovoltaic equipment.

[0005] In a first aspect, the present invention provides a voltage detection and control device. The voltage detection and control device is applied to a BUCK circuit. The BUCK circuit includes a solar photovoltaic panel and an electrical equipment. A relay switch is provided between the solar photovoltaic panel and the electrical equipment. The voltage detection and control device includes: an operational amplifier, the positive input terminal of which is connected to the voltage output terminal of the solar photovoltaic panel, and the negative input terminal of which is connected to the voltage output terminal of the electrical equipment; a comparator, the positive input terminal of which is connected to a first reference voltage, and the negative input terminal of which is connected to the output terminal of the operational amplifier; a switching transistor, the control terminal of which is connected to the output terminal of the comparator, the first pole of which is connected to the control terminal of the relay switch, and the second pole of which is grounded.

[0006] In some embodiments, the operational amplifier is used to output a first operational amplifier voltage according to the voltage difference between the solar photovoltaic panel and the electrical equipment; the comparator is used to output a second operational amplifier voltage according to the difference between the first operational amplifier voltage and the first reference voltage, so as to control the on and off state of the relay switch through the switching transistor.

[0007] In some embodiments, when the first operational amplifier voltage is less than the first reference voltage, the second operational amplifier voltage is a preset high level, and the switching transistor is turned on to disconnect the relay switch; when the first operational amplifier voltage is greater than or equal to the first reference voltage, the second operational amplifier voltage is a preset low level, and the switching transistor is turned off to close the relay switch.

[0008] In some embodiments, the operational amplifier is a differential amplifier, whose positive input terminal is connected to the voltage output terminal of the solar photovoltaic panel through a first resistor, the negative input terminal is connected to the voltage output terminal of the electrical device through a second resistor, and the output terminal is fed back to the negative input terminal through a third resistor.

[0009] In some embodiments, the gain coefficient A of the operational amplifier is determined by the ratio of the third resistor Rf1 to the second resistor RG1, A = Rf1 / RG1; the first operational amplifier voltage Vo1 is Vin*A, where Vin is the difference in voltage between the solar photovoltaic panel and the electrical device.

[0010] In some embodiments, the positive input terminal of the operational amplifier is also connected to a second reference voltage through a fourth resistor, and the second reference voltage is a forward bias voltage, which is used to keep the first operational amplifier voltage positive when the voltage difference between the solar photovoltaic panel and the electrical device is less than 0V.

[0011] In some embodiments, the preset low level is 0V, and the preset high level is the power supply voltage.

[0012] In some embodiments, the switching transistor includes a PNP triode or an NPN triode.

[0013] In a second aspect, the present invention provides a voltage detection and control method, which is implemented based on the voltage detection and control device according to any one of the first aspect. The voltage detection and control method includes: outputting a first operational amplifier voltage by the operational amplifier according to the difference in voltage between the solar photovoltaic panel and the electrical device; outputting a second operational amplifier voltage by the comparator according to the difference between the first operational amplifier voltage and the first reference voltage, so as to control the on-off state of the relay switch through the switching transistor.

[0014] In some embodiments, the step of outputting the second operational amplifier voltage to control the on-off state of the relay switch through the switching transistor includes: when the first operational amplifier voltage is less than the first reference voltage, outputting the second operational amplifier voltage as a preset high level to control the switching transistor to turn on, so as to disconnect the relay switch; when the first operational amplifier voltage is greater than or equal to the first reference voltage, outputting the second operational amplifier voltage as a preset low level to control the switching transistor to turn off, so as to close the relay switch.

[0015] The voltage detection and control device and method in the present invention have at least the following beneficial effects: The present invention provides a voltage detection and control device, which is applied to a BUCK circuit. The BUCK circuit includes a solar photovoltaic panel and an electrical device. A relay switch is arranged between the solar photovoltaic panel and the electrical device. The voltage detection and control device includes: an operational amplifier, whose non-inverting input terminal is connected to the voltage output terminal of the solar photovoltaic panel, and whose inverting input terminal is connected to the voltage output terminal of the electrical device; a comparator, whose non-inverting input terminal is connected to a first reference voltage, and whose inverting input terminal is connected to the output terminal of the operational amplifier; a switching tube, whose control terminal is connected to the output terminal of the comparator, whose first pole is connected to the control terminal of the relay switch, and whose second pole is grounded; wherein, the voltage detection and control device provided by the present invention can detect the voltage difference between the solar photovoltaic panel and the electrical device in real time through the operational amplifier, and amplify and process the difference signal, thereby significantly improving the detection sensitivity to minute voltage changes; the amplified voltage signal is input to the comparator and quickly compared with a preset first reference voltage. When the voltage difference is lower than the safety threshold due to an abnormal decrease in the photovoltaic panel voltage or an abnormal increase in the electrical device voltage, the comparator immediately outputs a control signal to drive the switching tube to act, and then controls the relay switch to quickly cut off the circuit connection. This design effectively suppresses noise interference through the operational amplifier amplification link, avoids misjudgment problems caused by too small signal amplitude or noise in the traditional scheme, and at the same time uses the fast response characteristic of the comparator to achieve a protection action speed of milliseconds. Compared with the traditional fuse or simple voltage detection scheme, it can identify potential risks and take protection measures earlier, thereby effectively preventing damages to the battery and photovoltaic equipment caused by abnormal working conditions such as input voltage direct connection and current backflow, and can effectively improve the reliability and safety of the system.

[0016] Other features and advantages of the present invention will be described in the subsequent specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained through the structures specifically pointed out in the specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings are used to provide a further understanding of the technical solutions of the present invention, and form a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation to the technical solutions of the present invention.

[0018] The present invention will be further described below in conjunction with the drawings and embodiments;

[0019] Figure 1 It is a circuit schematic diagram of a voltage detection and control device provided by an embodiment of the present invention;

[0020] Figure 2 It is a flowchart of a voltage detection and control method provided by an embodiment of the present invention;

[0021] Figure 3 It is another flowchart of a voltage detection and control method provided by an embodiment of the present invention.

[0022] Figure 4 It is an example flowchart of a voltage detection and control method provided by an embodiment of the present invention. Specific Embodiments

[0023] This part will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the drawings. The function of the drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention. However, it should not be construed as a limitation on the protection scope of the present invention.

[0024] In the description of the present invention, the meaning of "several" is one or more, the meaning of "multiple" is more than two, "greater than", "less than", "exceeding", etc. are understood as not including the number itself, "above", "below", "within", etc. are understood as including the number itself, "any one" means one or more, and "at least one of the following" and its similar expressions refer to any combination of these items, including any combination of single items or plural items. If the first and the second are described, it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0025] It should be noted that words such as "set", "installed", "connected", etc. in the embodiments of the present invention should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the embodiments of the present invention in combination with the specific content of the technical solution. For example, the term "connected" can be a mechanical connection, an electrical connection, or a connection that can communicate with each other; it can be directly connected or indirectly connected through an intermediate medium.

[0026] It should be noted that the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] Traditional BUCK circuits have significant safety hazards in photovoltaic charging or buck applications: when the buck MOSFET shorts due to a fault, the input voltage will directly reach the load or electrical device, causing damage to the device; in addition, when the photovoltaic voltage is lower than the voltage of electrical devices such as batteries, current backflow may occur, resulting in damage to the solar panel. Existing protection schemes mostly rely on fuses or simple voltage comparators. However, fuses have a slow response speed and cannot be reused, while ordinary voltage comparators lack dynamic amplification functions and are difficult to accurately detect small voltage differences, resulting in insensitive protection thresholds or frequent misoperations. Therefore, there is an urgent need for a BUCK circuit protection technology that can detect voltage differences in real time, quickly respond to abnormal states, and intelligently control on / off to solve the above problems.

[0028] Based on this, the purpose of the present invention is to solve at least one of the technical problems existing in the prior art. It can use an operational amplifier to amplify the voltage difference between the photovoltaic and the electrical device, and combine a comparator to set a reference threshold, significantly improving the detection sensitivity and detection speed of small voltage changes, avoiding misjudgments caused by noise or threshold deviations in traditional schemes, and effectively protecting the safety of electrical devices and photovoltaic devices.

[0029] The following will describe the solution of the present application with reference to the accompanying drawings. Refer to Figure 1 , Figure 1 is a circuit schematic diagram of a voltage detection and control device provided by an embodiment of the present invention; in a first aspect, the present invention provides a voltage detection and control device. The voltage detection and control device is applied to a BUCK circuit. The BUCK circuit includes a solar photovoltaic panel and an electrical device. A relay switch is provided between the solar photovoltaic panel and the electrical device. The voltage detection and control device includes: an operational amplifier, the positive input terminal of which is connected to the voltage output terminal of the solar photovoltaic panel, and the negative input terminal of which is connected to the voltage output terminal of the electrical device; a comparator, the positive input terminal of which is connected to a first reference voltage, and the negative input terminal of which is connected to the output terminal of the operational amplifier; a switch tube, the control terminal of which is connected to the output terminal of the comparator, the first pole of which is connected to the control terminal of the relay switch, and the second pole of which is grounded.

[0030] Among them, the voltage detection control device provided by the present invention detects the voltage difference between the solar photovoltaic panel and the electrical equipment in real time through an operational amplifier, and amplifies the difference signal, thereby significantly improving the detection sensitivity of small voltage changes; the amplified voltage signal is input to the comparator and quickly compared with the preset first reference voltage. When the voltage of the photovoltaic panel drops abnormally or the voltage of the electrical equipment rises abnormally, causing the voltage difference to fall below the safety threshold, the comparator immediately outputs a control signal to drive the switch tube to operate, thereby controlling the relay switch to quickly cut off the circuit connection. This design effectively suppresses noise interference through the operational amplifier amplification link, avoiding the misjudgment problem caused by the traditional solution due to too small signal amplitude or noise. At the same time, the fast response characteristics of the comparator are used to achieve a millisecond-level protection action speed. Compared with traditional fuses or simple voltage detection solutions, it can identify potential risks and take protective measures at an earlier stage, thereby effectively preventing abnormal operating conditions such as input voltage direct flow and current backflow from damaging the battery and photovoltaic equipment, and can effectively improve the reliability and safety of the system.

[0031] like Figure 1 As shown, the voltage detection control device in the solution of the present invention is Figure 1 The circuit structure shown realizes the protection function, and the various components work together as follows: the operational amplifier U1B constitutes a differential amplifier circuit, whose positive input terminal is connected to the solar photovoltaic panel voltage Vpv through the first resistor RG2, and the reverse input terminal is connected to the battery voltage Vbat through the second resistor RG1. By amplifying the voltage difference Vin=Vpv-Vbat by a preset multiple A, the output Vo1=Vin*A is sent to the comparator U2B; the reverse input terminal of the comparator U2B receives Vo1, and the positive input terminal is connected to the first reference voltage Vref2. When Vo1<the first reference voltage Vref2, the output high level drives the NPN transistor Q1 to turn on, so that the relay JK1 coil is energized and the main circuit is cut off.

[0032] In some embodiments, the buck circuit further includes a second capacitor C2, a buck MOSFET Q2, a diode D1, an inductor L1, and a first capacitor C1, which are sequentially arranged between the solar photovoltaic panel and the electrical device, to achieve buck voltage reduction, thereby making the battery or device operate more reliably and safely. The second capacitor C2 in the buck power circuit components can be an aluminum electrolytic capacitor for absorbing voltage spikes at the photovoltaic panel input, and a ceramic capacitor can be connected in parallel to filter out high-frequency noise. The buck MOSFET Q2 can be a low on-resistance MOSFET to cooperate with a PWM controller to achieve efficient buck reduction. The diode D1 is used for freewheeling protection and can be a fast recovery diode to provide a freewheeling path for the inductor L1 when the MOSFET is turned off, thereby preventing voltage kickback.

[0033] In some embodiments, the inductor L1 and the first capacitor C1 are used for energy storage and filtering. The power inductor stores energy and, in cooperation with C1, filters out the output ripple to ensure the stability of the load voltage. Furthermore, the difference Vin between the photovoltaic voltage Vpv and the battery voltage Vbat is amplified by an operational amplifier to enhance the detection sensitivity of small changes. When Vin < 0, Rf2 and Vref1 force Vo1 > 0 to ensure the effective operation of the comparator. The comparator can compare Vo1 with Vref2 (4V) in real time. If Vo1 < 4V (i.e., Vin < 0.04V), it is determined as abnormal, such as insufficient photovoltaic voltage or battery reverse injection. Furthermore, a high level is output to drive Q1 to conduct, causing the relay JK1 to cut off the main circuit within 3ms.

[0034] It can be understood that the protection mechanism of the BUCK circuit can be that the input capacitor C2 and the output capacitor C1 cooperate to suppress voltage fluctuations, and the MOS transistor Q2 and the diode D1 form a dual-path freewheeling. Even if Q2 is short-circuited, the relay can quickly isolate the fault.

[0035] In some embodiments, as Figure 1 shown, the operational amplifier is used to output the first operational amplifier voltage Vo1 according to the difference in voltage between the solar photovoltaic panel and the electrical equipment; the comparator is used to output the second operational amplifier voltage Vo2 according to the difference between the first operational amplifier voltage and the first reference voltage, so as to control the on / off state of the relay switch through the switching transistor.

[0036] In some embodiments, when the first operational amplifier voltage is less than the first reference voltage, the second operational amplifier voltage is a preset high level, and the switching transistor conducts to disconnect the relay switch; when the first operational amplifier voltage is greater than or equal to the first reference voltage, the second operational amplifier voltage is a preset low level, and the switching transistor disconnects to close the relay switch.

[0037] In some embodiments, the operational amplifier is a differential amplifier. Its non-inverting input terminal is connected to the voltage output terminal of the solar photovoltaic panel through the first resistor RG2, the inverting input terminal is connected to the voltage output terminal of the electrical equipment through the second resistor RG1, and the output terminal is fed back to the inverting input terminal through the third resistor Rf1.

[0038] In some embodiments, the gain coefficient A of the operational amplifier is determined by the ratio of the third resistor Rf1 to the second resistor RG1, A = Rf1 / RG1; the first operational amplifier voltage Vo1 is Vin * A, where Vin is the difference in voltage between the solar photovoltaic panel and the electrical equipment.

[0039] Among them, the operational amplifier U1B is connected to the solar photovoltaic panel voltage Vpv through the first resistor RG2 to the positive input terminal of the operational amplifier for impedance matching, and is connected to the battery voltage Vbat through the second resistor RG1 to the negative input terminal of the operational amplifier. Together with RG2, they form a balanced input network to ensure the common-mode rejection ratio. The third resistor Rf1 is used as a feedback resistor to connect the output terminal of the operational amplifier to the negative input terminal, and together with RG1, they determine the amplification factor. The gain formula is: A = Rf1 / RG1. For example, when Rf1 = 1MΩ and RG1 = 10kΩ, A = 100 times, and a small voltage difference (such as 10mV) can be amplified to 1V.

[0040] In some embodiments, the fourth resistor Rf2 is used to connect the positive input terminal of the operational amplifier to the second reference voltage Vref1. The second reference voltage Vref1 is a bias voltage source, which can ensure that when the photovoltaic voltage is lower than the battery voltage (Vin < 0), the output Vo1 of the operational amplifier is still positive, avoiding mis-triggering of the comparator.

[0041] In some embodiments, the comparator U2B can be divided by the resistor voltage division network formed by R3, R2, R4, and R5. It is connected to the power supply VCC through R3, the output terminal of the comparator through R2, grounded through R4, and connected to VCC through R5 to form a voltage division circuit. The reference voltage Vref2 can be calculated as: Vref2 = VCC*R4 / (R3 + R4); it can be understood that by introducing positive feedback through R2, a hysteresis window (such as ±0.5V) can be formed to prevent the comparator from frequently flipping due to voltage fluctuations.

[0042] In some embodiments, when Vo1 < Vref2, the device of the present invention can output a high level (such as VCC) to drive the switch tube to conduct. When Vo1 ≥ Vref2, the device of the present invention can output a low level (0V) to drive the switch tube to cut off; it can be understood that when the switch tube conducts, the relay JK1 is disconnected, and when the switch tube is disconnected, the relay JK1 conducts.

[0043] In some embodiments, when the switch tube Q1 is an NPN triode, the base resistor R6 is used to prevent overcurrent from damaging the triode, with a typical value of 1kΩ. The coil voltage in the relay JK1 is controlled by Q1. When it conducts, it attracts the contact to disconnect the main circuit. In addition, a freewheeling diode can be connected in parallel to the relay JK1 to suppress the back electromotive force when the coil is powered off.

[0044] In some embodiments, the positive input terminal of the operational amplifier is also connected to the second reference voltage Vref1 through the fourth resistor Rf2. The second reference voltage is a positive bias voltage, which is used to keep the voltage of the first operational amplifier positive when the voltage difference between the solar photovoltaic panel and the electrical equipment is less than 0V.

[0045] In some embodiments, the positive input terminal of comparator U2B is connected to power supply VCC through resistor R3 to obtain the first reference voltage Vref2. The positive input terminal of comparator U2B is also connected to the output terminal through resistor R2. One end of resistor R2 is grounded through resistor R4, and the other end is connected to power supply VCC through resistor R5.

[0046] In some embodiments, the preset low level is 0V, and the preset high level is the power supply voltage.

[0047] In some embodiments, switching transistor Q1 includes a PNP triode or an NPN triode, and the E terminal of switching transistor Q1 is connected to the B terminal through resistor R6.

[0048] In some embodiments, a temperature compensation module may be integrated in the generation circuit of the first reference voltage. The temperature compensation module includes a temperature sensor and an adjustable resistor network, and is used to dynamically adjust the threshold of the first reference voltage according to the ambient temperature to eliminate the influence of temperature drift on the voltage difference detection accuracy.

[0049] In some embodiments, the third resistor Rf1 of the operational amplifier can be replaced by a digitally programmable resistor network. The digitally programmable resistor network is connected to the microcontroller and dynamically adjusts the gain coefficient of the operational amplifier by receiving a control signal to adapt to the voltage difference range between the photovoltaic panel and the electrical device under different illumination conditions. A digital isolator is also provided between the input terminal of the operational amplifier and the photovoltaic panel and the electrical device. The digital isolator uses differential signal transmission technology to block the coupling influence of ground loop interference on the voltage difference signal.

[0050] In some embodiments, a configurable hysteresis circuit may be connected between the positive input terminal and the output terminal of the comparator. The hysteresis circuit includes a parallel-connected resistor and capacitor, and is used to dynamically adjust the hysteresis voltage window according to the system noise level to suppress false triggering caused by high-frequency interference. Further, a redundant switching device may be connected in parallel between the switching transistor and the control terminal of the relay switch. The redundant switching device is linked with the main switching transistor through a fault detection circuit. When the main switching transistor is detected to fail, it automatically switches to the redundant switching device to maintain the relay drive function.

[0051] In some embodiments, the power supply module of the operational amplifier and the comparator integrates a dynamic voltage regulation unit, which dynamically adjusts the supply voltage according to the system load status, reduces power consumption under light load, and improves signal processing accuracy under heavy load; in addition, the present invention may also include a wireless communication module, which is connected to the output end of the operational amplifier and the comparator, and is used to transmit the voltage difference detection data and the relay status to the remote monitoring platform in real time, and supports the configuration of the first reference voltage and gain coefficient through remote instructions, and then the voltage difference characteristic model of the photovoltaic system during normal operation can be established through the pattern recognition algorithm. When the real-time detected voltage difference signal deviates from the characteristic model, the early warning signal is triggered in advance, and a dual protection mechanism is formed with the hardware protection threshold.

[0052] refer to Figure 2 , Figure 2 : is a flowchart of a voltage detection control method provided by an embodiment of the present invention; in a second aspect, the present invention provides a voltage detection control method, which is implemented based on the voltage detection control device of any one of the first aspects, and the voltage detection control method includes at least the following steps:

[0053] Step S210, outputting a first operational amplifier voltage according to the voltage difference between the solar photovoltaic panel and the electrical device through the operational amplifier;

[0054] In step S220 , the comparator outputs a second op amp voltage according to the difference between the first op amp voltage and the first reference voltage, so as to control the on / off state of the relay switch through the switch tube.

[0055] refer to Figure 3 , Figure 3 is another flow chart of a voltage detection control method provided by an embodiment of the present invention; in some embodiments, outputting a second op amp voltage to control the on / off state of a relay switch through a switch tube includes at least the following steps:

[0056] Step S310, when the first operational amplifier voltage is less than the first reference voltage, outputting the second operational amplifier voltage as a preset high level, controlling the switch tube to be turned on, so that the relay switch is turned off;

[0057] Step S320: When the first operational amplifier voltage is greater than or equal to the first reference voltage, the second operational amplifier voltage is output as a preset low level, and the switch tube is controlled to be disconnected, so that the relay switch is closed.

[0058] It can be understood that in step S210, the operational amplifier collects the solar photovoltaic panel voltage Vpv and the voltage of the electrical device Vbat in real time through differential input, and amplifies the difference between the two, Vin, to the first operational amplifier voltage Vo1. By setting a reasonable amplification factor, the system can detect tiny voltage changes as low as ±5mV. Compared with the traditional direct voltage comparison scheme, the sensitivity is improved, effectively solving the problem of protection failure caused by too small voltage difference in the photovoltaic system under low light or shadow occlusion scenarios.

[0059] Further, in steps S220 and S310 to S320, the comparator compares the amplified Vo1 with the first reference voltage Vref1 in real time, and controls the conduction or cut-off of the switching tube according to the comparison result. When Vo1 < Vref1, a high level is output to drive the relay to quickly disconnect the main circuit; otherwise, the circuit is closed. It can be understood that by using a high-speed comparator and a low-delay switching tube, the total time-consuming of the system from detection to action can be effectively shortened, significantly reducing the risk of damage to the device under abnormal working conditions.

[0060] Reference Figure 4 , Figure 4 is an example flowchart of a voltage detection and control method provided by an embodiment of the present invention. Among them, the photovoltaic voltage Vpv is the voltage of the solar photovoltaic panel, and the battery voltage Vbat is the voltage of the electrical device. As Figure 4 shown, by judging whether the difference between the photovoltaic voltage Vpv and the battery voltage Vbat is normal, K is a set voltage constant (Vin = Vpv - Vbat ≥ K) for comparison. When the protection voltage Vin ≥ K, it is normal, the relay JK1 is closed, and the BUCK circuit outputs normally, and then it ends; when the protection voltage Vin < K, it is abnormal, the relay JK1 is disconnected, and ⑤ the BUCK circuit stops outputting, and then it ends.

[0061] In some embodiments, the method further includes the following steps:

[0062] Step S410: Collect the photovoltaic voltage Vpv and the battery voltage Vbat in real time, calculate the voltage difference Vin = Vpv - Vbat through a differential amplification circuit, and amplify Vin by a preset multiple A to obtain the first operational amplifier voltage Vo1 = Vin * A.

[0063] Step S420: Input the first operational amplifier voltage Vo1 to the comparator, and compare it with the temperature-compensated first reference voltage Vref1 in real time.

[0064] Step S430: If Vo1 < Vref1, it is determined that the photovoltaic voltage is insufficient or the battery voltage is backfed. The comparator outputs a high level (such as 5V) to drive the switching tube (such as the NPN transistor Q1) to conduct. After the relay coil is energized, the contacts are disconnected, and the BUCK circuit stops outputting;

[0065] Step S440: If Vo1 ≥ Vref1, it is determined that the system is normal. The comparator outputs a low level (0V), the switching transistor is turned off, the relay coil is de-energized and the contacts are closed, and the BUCK circuit outputs normally.

[0066] Step S450: Periodically detect the status of the relay contacts (for example, once every 10 ms). If it is detected that the contacts are stuck or abnormally disconnected, feedback to the microcontroller (MCU) through the optocoupler, trigger a fault alarm and start the redundant protection circuit.

[0067] It can be understood that during normal operation, the detected voltage Vin = Vpv - Vbat ≥ K in the voltage detection and control device (Vpv is the voltage of the solar photovoltaic panel, Vbat is the battery voltage, and K is the set voltage constant), the voltage Vol = Vin * A (A is the operational amplifier amplification factor). When Vin ≥ K, that is, the voltage Vol is greater than the operational amplifier reference voltage Vref2, the output voltage Vo2 of the comparator is a low level L (L = 0V), the relay JK1 is closed, and the main power circuit works normally; when an abnormality occurs in the main power circuit, the detected voltage Vin = Vpv - Vbat < K in the voltage detection and control device (Vpv is the voltage of the solar photovoltaic panel, Vbat is the battery voltage, and K is the set voltage constant), the voltage Vol = Vin * A (A is the operational amplifier amplification factor). When Vin < K, that is, the voltage Vol is less than the operational amplifier reference voltage Vref2, the output voltage Vo2 of the comparator is a high level H (H = VCC), the relay JK1 is disconnected, and the main power circuit stops working by disconnecting the output through the relay; thus ensuring that when the buck MOS transistor in the BUCK buck circuit is damaged and in a short-circuit state, the input voltage is directly connected to the power supply battery or device, damaging the device, making the BUCK circuit work more stably and the protection more intelligent.

[0068] The above has described the embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art. Within the scope, various changes can also be made without departing from the spirit of the present invention.

Claims

1. A voltage detection and control device, characterized in that, The voltage detection and control device is applied to a BUCK circuit, which includes a solar photovoltaic panel and an electrical device. A relay switch is provided between the solar photovoltaic panel and the electrical device. The voltage detection and control device includes: An operational amplifier, the positive input terminal of which is connected to the voltage output terminal of the solar photovoltaic panel, and the negative input terminal of which is connected to the voltage output terminal of the electrical device; A comparator, the positive input terminal of which is connected to a first reference voltage, and the negative input terminal of which is connected to the output terminal of the operational amplifier; A switching transistor, the control terminal of which is connected to the output terminal of the comparator, the first pole of which is connected to the control terminal of the relay switch, and the second pole of which is grounded.

2. The voltage detection and control device according to claim 1, characterized in that, The operational amplifier is configured to output a first operational amplifier voltage according to the voltage difference between the solar photovoltaic panel and the electrical device; the comparator is configured to output a second operational amplifier voltage according to the voltage difference between the first operational amplifier voltage and the first reference voltage, so as to control the on-off state of the relay switch through the switching transistor.

3. The voltage detection and control device according to claim 2, wherein When the first operational amplifier voltage is less than the first reference voltage, the second operational amplifier voltage is a preset high level, and the switching transistor is turned on to disconnect the relay switch; when the first operational amplifier voltage is greater than or equal to the first reference voltage, the second operational amplifier voltage is a preset low level, and the switching transistor is turned off to close the relay switch.

4. The voltage detection and control device according to claim 2, characterized in that The operational amplifier is a differential amplifier, its positive input terminal is connected to the voltage output terminal of the solar photovoltaic panel through a first resistor, its negative input terminal is connected to the voltage output terminal of the electrical device through a second resistor, and its output terminal is fed back to the negative input terminal through a third resistor.

5. The voltage detection and control device according to claim 4, characterized in that The gain coefficient A of the operational amplifier is determined by the ratio of the third resistor Rf1 to the second resistor RG1, A = Rf1 / RG1; the first operational amplifier voltage Vo1 is Vin*A, where Vin is the voltage difference between the solar photovoltaic panel and the electrical device.

6. The voltage detection and control device according to claim 4, wherein The positive input terminal of the operational amplifier is also connected to a second reference voltage through a fourth resistor. The second reference voltage is a positive bias voltage, which is used to keep the first operational amplifier voltage positive when the voltage difference between the solar photovoltaic panel and the electrical device is less than 0V.

7. The voltage detection and control device according to claim 3, characterized in that The preset low level is 0V, and the preset high level is the power supply voltage.

8. The voltage detection and control device according to claim 1, characterized in that, The switching transistor includes a PNP triode or an NPN triode.

9. A voltage detection and control method, characterized in that, Based on the voltage detection and control device according to any one of claims 1 to 8, the voltage detection and control method includes: Outputting a first operational amplifier voltage by the operational amplifier according to the voltage difference between the solar photovoltaic panel and the electrical device; Outputting a second operational amplifier voltage by the comparator according to the voltage difference between the first operational amplifier voltage and the first reference voltage, so as to control the on-off state of the relay switch through the switching transistor.

10. The voltage detection control method according to claim 9, wherein The outputting the second operational amplifier voltage to control the on-off state of the relay switch through the switching transistor includes: When the first operational amplifier voltage is less than the first reference voltage, outputting the second operational amplifier voltage as a preset high level, and controlling the switching transistor to be turned on to disconnect the relay switch; When the first operational amplifier voltage is greater than or equal to the first reference voltage, output the second operational amplifier voltage as a preset low level, control the switching transistor to turn off, so that the relay switch closes.

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